Cusp-press for tooth-crowns.



No. 668, 1"??? Patented Feb. l9, mm. c. A. COVALT. CUSP PRESS FOR TOUT CROWNS.

(Application filed July 14, 1900.)

(No Modal.)

INVENTOH WITNESSES A 770/?NEY8,

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CLIFFORD A. OOVALT, OF PHILADELPHIA, PENNSYLVANIA.

CUSP-PRESS FOR TOOTH-CROWNS.

SPECIFICATION forming part of Letters Patent No. 668,492, dated February 19, 1901.

Application filed July 14:, 1900- Serial NO- 23,561. (NO model.)

To aZZ whom it may concern.-

Be it known that I, CLIFFORD A. COVALT, a citizen of the United States, residing at Philadelphia, county 'of Philadelphia, and State of Pennsylvania, have invented a new and useful Improvement in Cusp-Presses for Tooth- (Jrowns, of which the following is a full,-clear, and exact description, reference being had to the accompanying, drawings, which form a part of this specification.

My invention relates to the manufacture of tooth-crowns from die-plates, and has for its object to improve the means for making the same.

It consists of a hinged die one member of which has a die-plate receptacle and means for operating said die. It also consists of means in the said construction for making the dieplate removable and for receiving die-plates for different kinds of tooth-crowns.

It also consists of a hinged die one member 'of which has the die-plate and the other member of which is provided with means for 7 containing a plastic material (preferably a metal, such as lead) which is adapted to force the gold or other material of which the crown is composed into the cusps of the die-plate.

It also consists of improved means for bringing the members of the die together and imparting pressure thereto.

In the drawings, Figure I is a plan of my improved die and actuating means therefor. Fig. 2 is a side elevation of the same. Fig. 3 is a section on line 3 3 of Fig. 1, and Fig. 4 is a detail perspective view of one of the members.

In the manufacture of gold tooth-crowns as ordinarily carried on a die-plate is provided which contains a number of difierent dies corresponding in character with the sevjaws A and B, the same constituting the two members of the die. I provide jaw A with a recess a, open at one side of the jaw, and the side walls of which slope inwardly toward each other from the base of the recess to the top surface of the jaw.

O is a die-plate for a single tooth. This die-plate has the cusps c. It corresponds in size with the recess a, and the side edges of the same slope outwardly from the face to the back, so that the die-plate may be inserted into the recess a and neatly fit therein and be held from accidental dislodgment.

D is a holding-plate which I have shown in the form of a right-angled piece of metal,the inner edges of which overhang the adjacent walls of the recess 00. After the die-plate C has been inserted in the recess a the edges of the gold-leaf are slipped under the overhanging portion of the holding-plate D and the gold-leaf is held in position overlying the dieplate 0.

The jaw B is provided with a depression 17, into which is inserted a piece of plastic material, ordinarily a bullet of lead.

When pressure is applied to bring the jaws A and B together with sufficient force, the lead is flattened out and forced toward the die-plate, which forces the gold into the cusps c, imparting to the gold the shape of the dieplate-t'. e., the shape of the crown which it is desired to make.

It may readily be seen that with the foregoing construction the die-plate is readily removable by sliding it out of the recess a, and any other die-plate of different superficial contour may be readily substituted.

I have devised the following constructions for securing the leverage required to cause the jaws A and B to approach each other with the required degree of pressure. The jaws are hinged together between their ends on the hinge or pin 6.

. F and F are two levers pivoted near their ends on the pins or hinges f and f, respectively. The lower end of each jaw has the lugs G G, and the short end of each lever has the lug H.

A and F are hinged together on the pivot 71, and the levers B and F are hinged together on the pivot t".

I I are plates or cheeks, one on each side,

By means of these lugs the levers having orifices for the reception'of the pins e, f, and f.

WVhen the levers F and F are brought together, the pivots i and 2" recede from each other; but the movement is very small, owing to the short distance between these pivots and the pinsf and f, and a correspondingly short movement will be given to the die ends of the jaws. By the described arrangement of compound levers the operation of the levers F and B" will bring the two jaws together with a pressure which I have found to be suflicien't to press the gold into the cusps and form the crown.

A slight looseness should be present between levers F F and pins ff. A.tightfit would obviously lock the levers from moving. The looseness need only be very slight, owing to the fact that the short ends of levers F F are moved through arcs intersecting lines drawn between a andfand e andf.

Having now fully described my invention, what I claim, and desire to protect by Letters Patent, is-

1. As anew article of manufacture, a cusppress for forming tooth-crowns consisting of two jaws, said jaws being hinged together, one of said jaws being provided with a recess for the reception of a removable cusp dieplate, and a plate secured to said jaw and overhanging the edge of said recess, substantially as described.

2. As a new article of manufacture, a cusppress for forming tooth-crowns consisting of two jaws, said jaws being hinged together,

one of said jaws being provided with a recess for the reception of a removable cusp dicplate, and the other of said jaws being provided with a depression for the reception of a bullet of plastic material, and a plate secured to the first-named jaw and overhanging the edge of said recess, substantially as described.

3. As a new article of manufacture, a cusppress for forming tooth-crowns consisting of two jaws, said jaws being hinged together, the upper jaw being provided with a recess for the reception of a removable cusp dieplate, and means secured to said jaw for retaining the gold-leaf in position under said cusp die-plate.

4. In acusp-press for forming tooth-crowns, the combination, with two jaws, the upper jaw being provided with a recess for the reception of a removable cusp die-plate and means for retaining the gold-leaf in position under said cusp die-plate, the two jaws being pivoted on a common hinge, of two operating-levers pivoted on separate hinges near, but not at, their ends, the short ends of said levers being respectively pivoted to the ends of said jaws.

In testimony of which invention I have hereunto set my hand at Philadelphia, Pennsylvania, 011 this 11th day of July, 1900.

CLIFFORD A. OOVALT.

Witnesses:

M. F. ELLIS, G. IRWIN HUTTON. 

